MIT cyclists generated 1.2kw to power a supercomputer in response to Google's "Innovate or Die" challenge.
SciCortex is new to the supercomputing field. With their relatively slow MIPs processors they don't have any contenders in the Top 500 list of supercomputers, but SciCortex is known for their development of very low power supercomputers, which is why bicyclists are able to power them.
My own employer brags about the lower power requirements of the "Constellation" High Performance Computing platform (I'm part of the development team), and the hardware and mechanical designers work hard and get industry awards optimizing power consumption and cooling, but the fact remains that higher clock speeds in the cores, memory and I/O means more juice is required for the system. Anyway, it's an exciting field to be in.
I've been meaning to mention Dekochari for nearly two years now. I forgot all about it and now Makezine has beat me to the punch. I have a collection of Dekochari photos around someplace that I'll post some day. Dekochari, BTW, are insane Japanese art bikes. Deko for decorated, and chari for "chariots" which is the Engrish for "bicycle" in Japan. Here's a good collection of photos and here's some more info from Pink Tentacle.